Air compressor unloader system

ABSTRACT

An air compressor unloader assembly for unloading the compression chamber of an air compressor during a compressor unloading cycle. The unloader assembly includes an unloader piston slidable within an unloader cylinder in the head of the compressor for slidably engaging the intake valve of the compressor and to hold the intake valve open for unloading of the compression chamber of the compressor pump. The unloading cylinder is accessible from an exterior surface of the head via a removable threaded plug in a gas tight arrangement. The plug is dimensioned whereby the unloader piston may be readily accessed for lubrication and/or removed for repair or replacement without having to remove the head from the air compressor cylinder.

BACKGROUND OF THE INVENTION

I. Field of the Invention

The present invention relates generally to air supply systems using reciprocating type air compressors, and more particularly, to compressor unloading systems which cause a pressure regulating mechanism or governor to displace an unloader piston to engage and hold the intake valve open during a compressor unloading cycle.

II. Description of the Prior Art

Piston type reciprocating air compressors are used to supply air under pressure for many purposes. The compressor pump is conventionally driven by either an electric or internal combustion engine. Each compressor pump incorporates a compression chamber closed off with a head and an intake valve and an exhaust valve in the head for regulated gas inlet to and gas outlet from the compression chamber. A compressor unloading assembly is provided for unloading the compression chamber during a compressor unloading cycle to reduce load on the motor when there is no demand on the compressor pump to provide compressed air, or to otherwise regulate the air pressure, particularly in continuous running type compressor pumps.

Normally the unloader system or assembly includes a pressure regulator, which is also known as a governor, located in the pressure line. The pneumatic control outlet of the governor is connected to an unloader piston which is thereby induced to slidably engage the intake valve and hold the same open to establish the unloading phase of the compressor.

The problem encountered with the unloader systems or assemblies of the prior art is that this unloader piston is not easily accessible for maintenance or replacement, and in deed, in some prior art compressor pumps the entire head must be removed to gain access to the unloader piston.

It is therefore a primary object of the present invention to provide an unloading assembly which is easily accessible for maintenance and repair.

SUMMARY OF THE INVENTION

The compressor unloading assembly of the present invention for unloading the compression chamber of the compression pump during a compressor unloading cycle is comprised of an unloader piston slidable with an unloader cylinder in the compressor pump head for engaging the intake valve of the compressor pump and to hold the intake valve open for unloading the compression chamber. This unloading cylinder is accessible from an exterior surface of the pump head via a removable plug which seals the unloading cylinder gas tihhy. For example, with a threaded plug. The plug is dimensioned whereby the unloader piston may be easily accessed for lubrication and/or removed for repair without having to remove the head from the compressor cylinder or having to remove difficult housing assemblies.

A pressure governor is provided and its inlet is connected to receive gas outlet under pressure from the compressor pump. Its outlet is connected to the unloader cylinder for moving the unloader piston to open the intake valve of the compressor pump with gas under pressure when a predetermined gas outlet pressure from the compressor pump has been attained. The unloader assembly is designed whereby the unloader piston slides downwardly toward the compression chamber to engage and hold open the intake valve.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages appear hereinafter in the following description and claims. The accompanying drawings show, for the purpose of exemplification, without limiting the invention or appended claims, certain practical embodiments of the present invention wherein:

FIG. 1 is an exploded isometric view of an air compressor incorporating the unloading assembly of the present invention; and

FIG. 2 is an enlarged exploded isometric view of the head of the air compressor shown in FIG. 1 illustrating some of the details of the unloader assembly of the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The basic air compressor illustrated is of conventional type, except for the unloading assembly of the present invention, and is a two cylinder single stage air compressor pump 10. Of course the unloading assembly of the present invention is also applicable to all types of gas or air compressors, including two stage compressors.

The compressor 10 includes generally a crankcase housing 11 enclosing the crankcase/piston assembly 12 with the pistons thereof reciprocally received within dual cylinder 13. On top of cylinder 13 is secured valve plate 14 which retains steel disc intake valves 15 and identical type steel exhaust valves 16. Head 17 is secured to the top of valve plate 14.

Air intake filter 18 is secured to inlet 19 for head 17 to filter intake air.

Typical fly wheel 20 with an internal cooling fan is provided on the end of the crank shaft/piston assembly 12.

The single stage compressor pump thus far described operates in a conventional manner well known by the prior art, with the exception of the unloading assembly provided in head 17, to be later described in detail. Accordingly, specific operation of the compressor pump need not and will not be described as this basic pump assembly has been readily available for purchase on the open market from Jenny Products, Inc. of Somerset, Pa.

The specifics of the unloading assembly of the present invention is incorporated into head 17.

The unloader assembly 30 of the present invention is comprised of unloader pistons 31 which are slidable within unloader cylinders 32 in head 17. Pistons 31 are slidable downward within cylinders 32 for engaging steel disc intake valves 15 and to hold them open for unloading compression chambers 21. The unloading cylinders 32 are accessible from exterior surface 33 of head 17 via removable threaded plugs 34. Plugs 34 seal cylinders 32 gas tight with O-rings 35.

The upper surfaces 36 of unloader pistons 31 are exposed to gas under pressure entering through inlet 37 in head 17 (see FIG. 2). Gas under pressure is fed to inlet 17 via conventional pressure governor 38 having an inlet 39 connected to receive gas outlet under pressure from compressor 10 via outlet 25 in head 17. Outlet 40 of governor 38 is connected to unloader cylinders 32 via inlet passage 37 for moving the unloader pistons 31 downwardly to open intake valves 15 with gas under pressure, as regulated by regulator 38, from compressor 10 when the pressure has attained a predetermined maximum.

The unloader pistons 31 are seated within unloader cylinders 32 by means of O-rings 41 and compression springs 42 serve to disengage unloader pistons 31 when the governor 38 is no longer applying gas under pressure to pistons 31. 

1. In a reciprocating gas compressor having a compression chamber closed off with a head and an intake valve and an exhaust valve in said head for regulated gas inlet to and gas outlet from said chamber, and a compressor unloading assembly for unloading said chamber during a compressor unloading cycle, said unloading assembly comprising: an unloader piston slidable within an unloader cylinder in said head for engaging said intake valve to hold said intake valve open for unloading said compression chamber, said unloading cylinder accessible from an exterior surface of said head via a removable plug sealing said unloading cylinder gas tight, said plug dimensioned whereby said unloader piston may be readily accessed and removed for repair without having to remove said head from said compressor cylinder.
 2. The unloading assembly set forth in claim 1, including a pressure governor having an inlet connected to receive gas outlet under pressure from said compressor and having an outlet connected to said unloader cylinder for moving said unloader piston to open said intake valve with gas under pressure when a predetermined gas outlet pressure from said compressor has been attained.
 3. The unloading assembly set forth in claim 2, wherein said plug is threadably received in said head.
 4. The unloading assembly set forth in claim 2, wherein said unloader piston slides toward said compression chamber to engage and hold open said intake valve. 